The hospital had received approval for the project from multiple city boards, including a conditional-use permit from the Planning Board in 2012, but then "they just let it lapse," City Principal Planner Rick Taintor said Tuesday.

So now the hospital has to go through the application process again, Taintor said, including stops before the Planning Board on Thursday night, the Board of Adjustment and the Conservation Commission.

The hospital is scheduled to go before the Board of Adjustment on July 22 for a special exemption, which previously dealt with such issues as noise after concerns were raised by members of the Coakley Road neighborhood, Taintor said.

Nancy E. Notis, associate director of marketing and public affairs for the hospital, said the hospital has resubmitted the proposal for the helipad "because the timing is right for us now in pursuing the trauma certification."

The move "will allow us to better manage our patients," Notis said Tuesday.

The Portsmouth Herald reported in June that the hospital was preparing to apply to the state of New Hampshire to become a Level II trauma center.

Nick Mercuri, bureau chief of EMS for the New Hampshire Department of Safety, said the hospital has not yet filed an application with the state, but he's been talking to hospital officials about their plans for the application.

If the hospital receives the upgraded status — Level I is the most serious and Level IV is the least serious — they will be allowed to treat and retain more serious cases than they can now, Mercuri said.

"Patients with a higher level of acuity can go there and they'd be able to retain more patients, instead of transferring them out to a higher level of care," Mercuri said.

Building the helipad will allow the hospital to "get people to our facility faster," Notis said. "It's all part of better managing our patients when time counts."

Right now, emergency patients are flown into the Portsmouth International Airport at Pease and then brought to the hospital, Notis said.

"It's a critical component of providing the best care when timing is important," Notis said, adding, "We do have the support of EMS on the plan."

If approved by city boards, Notis said the hospital will begin work on the helipad "as soon as possible" and hopes to have it completed by the end of the year. The hearing scheduled before the Planning Board on Thursday will focus on whether the board should grant a conditional-use permit for "work within the wetland and wetland buffer," according to a memo Taintor prepared for Planning Board members.

But Taintor states in the memo, "The applicant is proposing to construct the helipad in an already paved part of the wetland buffer, in the area of the existing parking lot that is closest to the hospital emergency room. This is the most suitable location for the proposed helipad and will have minimal impact on the wetland."

In order to provide "the minimum clear zone necessary for the helicopters," the hospital is proposing to cut some brush from the "wetland adjacent to the site for a total of 2,042 square feet," according to Taintor's memo.

He concludes that the wetland area impacted is "a small portion of a much larger wetland complex and the proposed cutting should not significantly impact the overall wetland functions and values."

Documents filed by the hospital with the city assert that the "need for a helipad supports the hospital's near- and long-term service needs that ultimately translates to a higher level of care for the residents, workers and travelers in their service area."

Thursday's Planning Board meeting is scheduled to begin at 7 p.m. in City Hall.